So many pioneers and others are so used to saying, "Sorry, I can't help you move" or "Sorry, I can't take an elderly sister to her medical appointment" with the excuse: "....because I have to get my time in."
I know Ray Franz tried to indicate that sacred service included good works toward others and it was shot down because Watchtower was still building a massive printing empire and didn't want members to skip selling magazines to do something more important.
I would say that literature give-aways are becoming such a burden now, with the dubs not really donating for them much, that the cart witnessing without bothering people still isn't enough. They actually do not want too many magazines/books to go out the door. So allowing other things to "count time" on will further reduce the efforts to give away Watchtower mags.
I think that maybe the only reason they don't stop literature distribution is that it is the main method they use to control the members' activities- make them "publishers" and "pioneers." Taking that away would just be too radical a change for the members to swallow.
I see this as another sign that they are in true money trouble, not just pretending. But I also consider that part of their money problem might have included moving massive amounts to offshore accounts as a golden parachute for the lawyers, accountants, Governing Body members.